Apparatus for die casting



Feb. 5, 1935. W MA LESTER 1,989,812

APPARATUS FOR DIE CASTING Filed Feb. 5. 1932 4 Sheets-Sheet l /3 @y j r W i *i E; wir! l Fia- 53 7065 ea 52 69 r/ 75 53 53 ,ro 65 68 52 es 7/ 73 5.?

i u u www@ Feb. 5, 1935. w. M. LESTER 1,989,812

APPARATUS FOR DIE CASTING Filed Feb 5. 1932 l 4 Sheets-Sheet 2 l/l/llI/ll//Illllll/.rl/ lll/1111111111111',O

INVENTOR.

94% 0MM g/ ATTORNEY.;

Feb. 5, 1935. w, M. LESTER 1,989,812

APPARATUS FOR DIE CASTING Filed Feb. 5, 1932 4 Sheets-Sheet 3 6 J, M e 0 7 M W Q m 15 A 9 A 7 ,W e. 7% 6 y B A & .7 o 3 3 4. 6 5 0 n0 5 v w 4 w w 3 Feb. 5,- 1935.

W. M. LESTER APPARATUS FOR DIE CASTING Filed Feb. 5. 1932 4 Sheets 5heet 4 INVENTOR. /z//zmf /Y [6522er QZWOM@ ATTORNEYJZ Patented Feb. 5, 1935 v yUNITED STATES PATENT OFFICE 1,989,812 APPARATUS Fon DIE cAs'rmG William M. Lester, Shaker Heights, Ohio Application February 5, 1932, Serial No. 591,184

3 Claims.

My prevent invention relates to the art of die casting or to the manufacture of nished metal castings by forcing molten or plastic metal under pressure into a metallic mold. The subject matter of the present invention'is related to and includes certain novel improvements over my co- -pending application Serial No. 561,676, led September 8, 1931.

The hereindescribed die casting method and machine are'particularly applicable to the commercial production of die castings of the higher melting point alloys such as copper, brass and bronze allloys. More precisely my invention has for its object the provision of an automatic mode of operation capable of producing completed castings in quantity production at the rate of about two hundred and iifty (250) pieces per hour. Further objects include the provision of automatic single control means, a co-related hydraulic actuating system, and independently movable closure slides for cooperating with th'e metal extracting reservoir. Additional objects shall become apparent as the following description proceeds. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following d scription set forth in detail certain means and one mode of carrying out the invention, such disclosed means and mode illustrating, however, but one of various ways in which the principle of '.the invention may be used.

In said annexed drawings:

Fig. 1 is a'. side elevation of the exterior of a die casting machine constructed according to the principles of my invention; Fig. 2 is a vertical sectional view of Fig. 1; Fig. 3 is a transverse vertical section taken substantially upon line 3-3 of Fig. 2 in the direction of the arrows; Fig. 4 is an enlarged sectional detail of a portion of one of the hydraulic actuating cylinders; Fig. 5 is an enlarged sectional detail view of the construction of the metal lift and slide cylinders, with the major elements resolved into a single plane for the purpose of convenience of description; Figs. 6 and 7 are enlarged detail views of the metal lift and slides in varying positions in relation to the melting pot; Fig. 8 is a diagrammatic illustration of the automatic hydraulic actuating system; Fig. 9^is la diagram illustrative of the sequence of operations of the automatic hydraulic actuating system; Figs. 10 to 13 inclusive are diagrams showing the various positions of the master control valve during one complete cycle of operation.

` Now directing attention more particularly to Figs. l, 2, and 3, my die casting machine consists of the main base casting 1 and melting pot housing 2, above which is mounted the fixed frame composed of the vertical end members 3 and 4 which are rigidly secured to each other by means of the horizontal rods 5. The vertical end member 3 may be variably spaced from the endmember 4 by means of varying the position of the fastening nuts on the cross rods 5. A pair of die plates 6 and 7 are mounted upon the cross rods 5. Die plate 6 is adapted to carry the movable die bolster 8 and the die mold 9. The die plate 7 carries the die mold 7 and is relatively fixed, while the die plate 6 is horizontally movable by means of the hydraulic cylinder 10 and toggle link mechanism 11. Additional hydraulic operating cylinders are assembled on the frame and consist of the plunger cylinder 12, the metal lift cylinder 13, and the ejector cylinder 14. 'I'he ejector cylinder 14 is carried by the movable die plate 6 and is adapted to reciprocate the plate 15 to which are secured ejector pins 16extending through the die 9. 'I'he vertical metal lift cylinder 13 carries the piston 17 which is connected by means of the rod 18 to the metal lift reservoir 19. The die plate 7 is engaged by the compression coil springs 20 upon the rods 5, whereby it is forced against the frame. end 4. When the dies are in locked position as shown in Fig. 2, however, by virtue of the pressure exerted by the toggle link mechanism 11, the die plate 7 is forced against the reservoir 19, tending to maintain the latter in locked' registered position with the plunger 21. The plunger 21 is adapted to pass into and through the' interior of the metal reservoir 19, and is reciprocably operated by means of the piston rod 22 and piston 23 in the hydraulic cylinder 12.

A melting pot 24 is disposed below and in the vertical line of travel of the reservoir 19. An appropriate type of furnace construction, adapted 'to utilize a gas, electric, or solid fuel heating means; surrounds the melting pot 24 and is enclosed within the housing 2. A pair of vertically reciprocable closure plates extend from the bottom of the end plate 4 and the die plate 7 to a point slightly above the liquid level in the melting pot 24. Directing attention to Fig. 3, the closure plates or slides 25 and 26 are secured to the cross head member 27 by means of suitable bolts and clamping plates. A pair of vertically extending arms 28 and 29 connect the cross head 27 to the piston rods 30 and 31. The piston rods 30 and 31 in turn carry the pistons 32 and 33 in the vertical cylinders 34 and 35, which are positiond on opposite sides of the uf: cyundema. The last described mechanism is adapted to impart a vertical reciprocal movement to the closure plates 25 and 26, which movement is of suflicient length to immerse the lower ends of the plates 25 and 26 slightly below the liquid level of the metal in the melting pot 24 substantially as shown in Fig. 7.

The melting pot furnace may be mounted upon ception oi the closure plates 25 and 26, is positioned over the top of the furnace. Y Now directing attention to Figs. 2,' 3, d and 7,

[the cycle of operation of the above described parts' e, may be simply outlined as follows. Starting from the position as shown in Fig. 2, the metal reservoir 19 travels downward and is totally'immersed beneath the level of the metai in the melting pot l 24, -as shown in Fig. 7. in the meantime the dies f 8 and 9 have been opened and the pressure upon the die plate l has heen remcved and the correspending binding pressure upon the ends of the reservoir 19 has been likewise removed whereby such reservoir 19 is permitted `to proceed upon its downward travel. While the reservoir 19'has reached its lowermc-st position in the Ikmelting pot 24, the closure plates 25 and 26 have also traveled to their lowermost position as shown in Fig. 7.-, ln the next stage oi operations, referring to Fig. d, the reservoir i9 begins its return upward stroke with a charge of metal retained in its interior cavity by virtue of the closing action or the end plates 25 and 26. The plates 25 and 26 accc-mpany the reservoir 19 along that portion of its travel between the melting pot and the bottom oi the end plate 4 and die plate 7. When the 'reservoir 19 has reached its uppermost position,

Vas shown in Fig. 2, the link mechanism locks the dies 8 and 9 and also exerts a locking pressure on the ends of the reservoir 1 9 between the die plate 'I and the end plate 4. The plunger 21 then passes `into the reservoir 19, forcing the metal contained As has been hereinbefore indicated, metansv are Y provided for the actuation of theelements pierforming the above outlined casting cycle which include the hydraulic actuating cylinders 10,., 12, 13 and 14. In order to prevent hammering and knocking actions in these hydraulic cylinders, a by-pass and` throttling valve construction is provided whereby a cushioning action imparted to the nal portion ef the stroke of the piston in such cylinders. This latter construction is illustrated in greater detail in Fig. 4, which is an enlarged detail section taken from the head end of the plunger cylinder 12.

Referring now to Fig. 4, the hydraulic pressure inlet or outlet passage 40 as the case may be. depending up'c-n which direction the piston is traveling, leads intoy the side of the cylinder at a point substantially adjacent the end. A second passage 41 ieads around to the end of the cylinder. In the passage 41 there is disposed the automatic threttling valve 42 which is adapted to hear against the beveled scat 43 in such passage.` A plurality of openings 44 communicate from the portion oi.' the throttle valve 42 bearing against the bevel seat to the interior of the valve. A thrcttling passage 45 is provided in the central portion of the transverse abutment to the valve lines. the exhaust liquid be free -to pass out vthe hydraulic cylinder, Ithf l.passage and a return il,

means for automatic mechanical 4:ma D arche cam track seas-indicated mr'g. 9.

masacre directly through the passage 4d. Hc-wever, when the walls ci the piston 23 attain such a position as to close the outlet passage 40 in the well of the cylinder, it will then'be necessary for any exhaust liquid to pass through the throttle valve opening 5 45, thereby offering a substantial resistance to the `travel of the piston, and correspondingly impart- 4ing a cushioning action to the ilnal portion of the piston stroke. When hydraulic pressure is admitted to the passage 40, liquid will travel through 1c the secondary passage 4i to the throttle valve 42, forcing the latter away troni the beveled seat 43, thereby giving access to fluid new through the inclined openings 4e, and substantially relieving the throttling effect oi the single opening 45.

, Similar throttlingl valves 46 and 46 are provided inthe Ahead and rod ends of the liftl cylinder 13 respectively; likewise, throttling valve 47 in the head end oi? the ejector ,cylinder 14 and valves 48 and 49 in the rod and head ends oiI the liquid gc cylinder lil. Although the length of the secondary py-passes in the cylinders lil, 13 and i4 may be vadried in order to obtain increased cushioningactionthe construction ci the icy-passes and tarottling valves is substantially equivalent t lustrated in Fig. 4. ,I 'i

Since itis contemplatedtoproy K K tary control means for co-relatingthe way valve 50 havingfithedouble pis n and a )pluralityV of annular hi adapted to be vplaced,` in co other at variousfinterval of such plunger 51,. The rnl supply pipe 52 is connect nected to each end of sai and 53 may .be connes. draulicpressure pump norr described hereinvfsi knQWn 52.192152 may and gearfsieyiitothe expansiones-tipe hand 1ever 56';` or, as in the caseI oigcont automatic operation, a lever lfulcruined 0iegpoint 57' and .connected by means 5810 the cam. track 59 of the revlu'nle disc---GQ-'fprovides a valve acticn. A suitable worm r, mechanism 61 and electric driving be satisfactory for the purpo: Qfrgrotatingg-rthe cam disc 60. It will thus be seenthat rotation o f the cam disc 60 will impartareciprocal move- 55 ment tothe valve plunger 51;. hereby various predetermined hydraulic pressur nneetions wilfA be made to the actuating cylinder 5,3

" Referring to Figs. 8 to 13 inclusive, operation of the hydraulic pressure actelatixig` system is as follows.: At the beginningof thczcycle ,onoperations, the valve plunger 51 is ing-,thc,-pccition ,as indicated in Fig.'11 anddenomlnatedias tion B. Such pesltion B corresponds B of thecam track 59 fas. indicated in Figz 'lhe remainder of the valve positionshown y,in-Figs 10, 12 and V13 and therein labeiedpositicns, D, respectively, likewise ccrrespcndtoarca -,-f,C;-A

Now directing attention mo A to Figl.8,when the valve plunger-ici position B, the hydraulic pressure suppl? P1P@ 1S placed in communication with pipe B5 leading to@ the foot valve 66,v pipe 67, and the rod end of the ejector cylinder 14. Pressure supply is also in .75

communication with pipe 68 to the rod end of the lift cylinder 13; and pressure supply also leads through the pipe 69 to therod end of the plunger cylinder 12. The foot valve 66 is set at a pressure of about two hundred`(200) pounds per square inch in order that the ejector cylinder 14 will be closed before pressure is admitted to the head end of the link cylinder 10. It will thus be seen that when the valve plunger. 51 is in position B that (1) the plunger 21 is withdrawn, (2) the metal reservoir 19 is raised to its uppermost position, (3) the ejector pins 16 are in closed position, and (4) the link cylinder 10 is closed and locked to the die mechanism.

Since the revolving cam track 59 turns in a counterclockwise direction as indicated by the arrow in Fig. 9, the next position to which the valve plunger 5l moves is position D. In position D the pressure supply pipe 52 is placed in communication with the pipe 69 to the rod end of cylinder 12, with the pipe I3 through the pipe '74 to the head ends of the slide cylinders 34 and 35, to the two-way check valves '75 and '76, and to the head end of the reservoir lift cylinder 13; and also in communication with the pipe 71 through the foot valve '72 to the rod end of the link cylinder 10. It will thus be seen at position D that (1) the pressure is maintained upon the rod end of the plunger cylinder retaining the plunger 21 in withdrawn position, (2) the closure slides 25 and 26 are moved to their lowerrnost positions, (3) since the check valve '75 is set at about two hundred (200) pounds per square inch pressure will next be admitted to the head end of the lift cylinder 13 tending to force the metal reservoir 19 on its downward stroke, but, inasmuch as the locking pressure is still exerted between die plate '7 and the end plate 4, the

metal reservoir 19 will be retained in position until enough pressure is built up against the check valve '72 which is set at about four hundred (400) pounds per square inch), starting the link cylinder piston on its backward stroke and opening the locked plates '7 and 4; (4) when the link cylinder piston has passed the opening 77 in the wall of the cylinder 10 pressure will be admitted to the head end of the ejector cylinder 14 through the pipe 7'7' and the ejector pins 16 will be moved to their outward position.

The valve plunger 51 in its next movement assumes position C, as shown in Fig. 12. In position C, hydraulic pressure is admitted through the pipe 52 to pipe 68 to the rod end of the reservoir lift cylinder 13, pressure is admittedto pipe 69 to the rod end of plunger 12, and pressure is admitted to pipe 61 to the rod end of the link cylinder 10. It will thus be seen that in position C (1) the plunger 21 is maintained in withdrawn position, (2) the link mechanism and dies are maintained in open position, (3) the ejector pins remain in outward position and, (4) the metal reservoir 19 ascends to its uppermost position in conjunction with the upward movement of the closure slides 25 and 26. The last mentioned contemporaneous movement of the slides 2,5 and 26 is accomplished automaticallyby means of the construction indicated in Fig. 5, in

which the slide cylinders 34 and 35 together with their connecting passages to the metal lift cylin-V der ,'13 have been resolved into a common plane for the purpose of convenience in description. In

Fig. 5 it will be seen that pipe 68 communicates with the rod end of the lift cylinder 13 and also with the passages '78 and 79 which, in turn, lead to the rod ends of the slide cylinders 34 and 35, respectively. A pair of check valves 80 and 81 are placed in the passages '78 and '79 so that when pressure is admitted through the pipe 68, it will not be possible for any fluid iiow into the cylinders 34 and 35 until the lower end of the piston 1'7 has passed the openings in the wall of the cylinder 13. When the piston 17 has reached such position, viz., after the metal reservoir 19 has proceeded partially upon its upward stroke, fluid pressure will then be conducted by means of the passages 82 and 83 to the rod ends of slide' cylinders 34 and 35, so that the closure slides 25 and 26 will accompany the metal reservoir 19 in its passage between the liquid level of the melting pot and the bottom of the plates '7 and 4.

Again referring to Fig. 5, the purpose of the check valves 80 and 81 is to prevent immediate uid passage to the rod ends of cylinders 34 and 35, but to permit a return passage in the opposite direction when the slides 25 and 26 are on their downward stroke.

In the chronological sequence of operations, the valve plunger 51 next moves from position C to position B, the function of which has already been described.

The last stage of the cycle of hydraulic control involves the movement of the valve plunger 51 from position B to position A. In position A, hydraulic pressure is maintained upon the pipes 68 and 65 and initially supplied through the pipe '70 to the head end of the plunger cylinder 12. The effect of such valve movement to position A is to (1) maintain the dies in locked position, (2) maintain the metal reservoir 19 in slides 25 and 26 in uppermost position and, (3) to force the plunger 21 into and through the metal reservoir 19, lthus completing the cycle of operations.

It should be noted that in each of the above described valve positions that those pressure lead pipes which are not placed in communication with the hydraulic pressure supply pipe 52, are in com- "pose of illustrating the relative time intervals consumed by each of the valve positions:

Aro Time Sec. Valve Position A-Plunger shoots metal 50 2 B-Plunger withdrawmcasting 'solidiiies 62 2. 5 D-Die opens, metal reservoir 4 38 1. 5 B-Die closes 62 2.5

Tntnl 312 12. 3 Valve movements 48 l. 9

Tnm 360 14. 4

explained, change being made as regards the means and the steps herein disclosed, provided those stated by any of the following claims or their equivalenti be employed.'

I therefore particularly point out and distinctly claim as my invention:

l. in a die casting machine, the combination of a'pressure plunger, openable die blocks positioned in spaced relationship in respect to said plunger, a sprue opening in one of said blocks, a melting pot located adjacent said plunger and said die blocks, a container for fluid metal movable from said melting pot to a position in registry with and in the space between said plunger and said sprue opening, an opening in said container for the reception of said plunger, an opening in the other end of said container for ejection of metal, and a pair of reciprocable closure plates adapted to cover said last-named openings when said container is withdrawn from said melting pot.

2. In a die casting machine, the combination of a pressure plunger, openable die blocks positioned in spaced relationship in respect to said plunger, a spzue opening in one of said blocks, a melting pot located adjacent said plunger and said die blocks, a container for uid metal movable from said melting pot to a position in registry with and in the space between saidplunger and said sprue opening, an opening in said container for the reception of said plunger, an opening in the ther end of said 'container for ejection of metal, and a pair of reciprocable-closure plates adapted to cover said last-named openings when said container is withdrawn from said melting pot, hydraulic pressure means for moving said plunger, said die blocks, said container and said closure plates, and a single control valve for supplying hydraulic pressure to said moving means in a predetermined cycle of operation.

3. In a die casting machine, means for extracting individual charges of metal from a main supply source comprising the combination of a die plate, a second plate spaced from and parallel to said plate, a melting pot, a iiuid metal container movable between said plates and into said melting pot, openings in opposite ends of said metal container, movable closure members for said openings when said container is moving between the ends of said plates and said melting pot, means for moving said container and said closure members, automatic means for actuating said closure member moving means after said container moving means has begun itsv stroke, and a pressure plunger disposed in the face of said second plate and insertablethrough said metal container.

t WILLIAM M. LESTER. 

